1. Field of the Invention
The present invention relates to a warp-knit tape for a slide fastener, which is formed of a warp knitting structure, wherein a longitudinal stretch and contraction of a coupling element mounting portion are suppressed and tape main body portion has a property to longitudinally stretch and contract, and particularly relates to a warp knitting tape for a slide fastener having a structure wherein the coupling element mounting portion and a tape main body portion act independently of each other.
2. Description of the Related Art
Recently, a slide fastener is frequently used for clothes in fashion and underwear. Conventionally, the slide fastener is frequently used for elastic clothes such as clothes made of knitted cloth or highly elastic sportswear. In order to make the slide fastener applicable to the above various elastic clothes, a weaving structure, a knitting structure, or material of constituent yarns of the slide fastener tape is selected in weaving or knitting the tape, the coupling element mounting portion on a longitudinal edge of the tape is made inelastic, and the remaining tape main body is provided with elasticity in a longitudinal direction.
There is a conventional slide fastener tape as disclosed in Japanese Patent Laid-open Publication No. 49-88645, for example, wherein inelastic warp yarn is used for forming the coupling element mounting portion so as to suppress longitudinal elasticity of the coupling element mounting portion, while elastic yarn is used as the warp for forming the tape main body portion so as to provide longitudinal elasticity to the tape main body portion. The coupling element mounting portion is inelastic in order to prevent a chain split, i.e., prevent the coupled elements mounted to the coupling element mounting portion from being detached from each other and to prevent the fastener from opening due to pulling forces applied from all directions to the clothes which stretch and contract in response to movements of a body, when the elements of the slide fastener are coupled.
If the coupling element mounting portion is made completely inelastic as described above, a strained phenomenon is generated in a slide fastener mounting portion and a significant disharmony in appearance is generated in the clothes, at the time of an intense exercise such as bending and stretching of the body. In order to eliminate this defect, there is a slide fastener as disclosed in Japanese Patent Laid-open Publication No. 63-294804, wherein a stretch degree of at least an edge side of the coupling element mounting portion of the fastener tape including the edge side of the coupling element mounting portion in a longitudinal direction is set at 10% or more. The stretch degree is controlled in such a range that a pitch of the coupling elements at the time of stretch is less than a double of a height of the coupling head, and the pitch of the coupling elements is varied in accordance with stretch and contraction of the edge side of the coupling element mounting portion. Moreover, because the pitch variation is within a range of a value smaller than the double of the height of the coupling head, the coupling elements are not detached from each other even if the coupling element mounting portion stretches.
However, in the above fastener tape disclosed in Japanese Patent Laid-open Publication No. 63-294804, if the tape main body has such an elasticity that the tape main body stretches and contracts following the stretch and contraction of the highly elastic clothes, for example, a difference between the stretch degrees of the tape main body and the coupling element mounting portion is increased. As a result, it is impossible to eliminate disharmony of clothes in appearance, which has been a conventional desire.